What the FDA labels say about taking them together
Quinidine and siponimod
Siponimod's FDA label of June 30, 2026 names quinidine in its drug interactions section; the quinidine label PlainMeds reads does not name siponimod.
Check it at the source: the quinidine FDA label on DailyMed (effective February 1, 2018, Sun Pharmaceutical Industries, Inc.); the siponimod FDA label on DailyMed (effective June 30, 2026, Novartis Pharmaceuticals Corporation).
What does the quinidine label say about siponimod?
Quinidine's label (effective February 1, 2018) does not name siponimod in these sections. A label lists what its studies and reports found; it is not a complete list.
Source: FDA drug label (Quinidine Gluconate), Sun Pharmaceutical Industries, Inc., effective February 1, 2018 (SPL set 5023f053-fcc4-4c2c-aa59-9ec198ad185e), via openFDA; the full label on DailyMed
What does the siponimod label say about quinidine?
Siponimod label, drug interactionsClass Ia (e.g., quinidine, procainamide) and Class III (e.g., amiodarone, sotalol) antiarrhythmic drugs have been associated with cases of Torsades de Pointes in patients with bradycardia.
Source: FDA drug label (MAYZENT), Novartis Pharmaceuticals Corporation, effective June 30, 2026 (SPL set 44492772-5aed-4627-bd85-e8e89f308bb3), via openFDA; the full label on DailyMed
These are the labels' own sentences. PlainMeds does not grade interactions; a pharmacist or prescriber can say what they mean for one person's medicines.
Both medicines on the record
| Quinidine | Siponimod | |
|---|---|---|
| Labeled for | Atrial fibrillation | Multiple sclerosis |
| Boxed warning | Yes | No |
| Pharmacy cost (NADAC) | $4.92 per tablet 324 mg tablet | n/a |
| Shortage now | No current entry | No current entry |
Source: FDA NDC Directory, CMS NADAC of October 7, 2026 and the FDA Drug Shortage Database (FDA files October 8, 2026)
What next?
- Check more medicines together
- up to five at once